Pure gases or gaseous mixtures are now filled into cylinders or frames carrying a group of cylinders. They are filled in a filling installation and then brought to the site of utilization of the gas.
So as to permit the filling of containers with gases of different compositions and under different pressures, the filling installations conventionally comprise a network of valves permitting selectively connecting to the container to be filled an assembly of sources of supply gas.
To ensure filling of the container with a gas satisfying a predetermined specification, the opening and closing of the valves is at present entrusted to an operator. The latter opens and closes the different valves, at predetermined moments, and according to a predetermined sequence. The operation of such an installation therefore requires the continuous presence of an experienced operator who determines the sequence of operations.
It has been proposed to replace manual valves by control valves connected to a drive unit adapted to control the condition of the valves for filling a receptacle with a gas according to the predetermined specification.
In such an installation, the drive unit is adapted to receive at its input the specifications of the gas to be introduced into the container. The input data consist particularly in the mass composition, or in the pressure of the different components constituting the gas. Thus, the information input into the drive unit is the result relied on for the filling operation.
Such a filling installation requires an extremely complex drive unit whose program that is utilized depends both on the physical structure of the network of valves used and on the nature of the gases to be introduced.
By way of example, FR-A-2.713.105 describes an installation for filling a reservoir with a gaseous mixture. This installation comprises a computer driving the cyclic opening and closing of valves arranged between the reservoir and sources of gas under pressure. The computer receives as its controls the composition relied on to effect the mixture. It is adapted to predetermine and carry out a cycle for driving the various valves so as to obtain the desired mixture.
Moreover, JP-2675633 describes an installation for filling cylinders comprising several sources of gas that can supply selectively the cylinders under the control of a control unit. The operational steps of the control unit and the input variables are not disclosed.